1. Field of the Invention
This invention relates to apparatus and process for conversion of solar to electrical energy using a solid state photoelectrochemical cell. Particularly, this invention provides a solid state photoelectrochemical cell having insitu electrochemical energy storage. The conversion of solar to electrical energy may be carried out using a homogeneous solid electrolyte matrix crystal lattice structure having a central electrolyte separator portion providing ionic conductance, an oxidant portion having first redox couples in fixed lattice positions on one side of the separator portion and a reductant portion having second redox couples in fixed lattice positions on the other side of the separator portion, both the oxidant and reductant portions possessing electronic and ionic conductivity; at least one photosensitive photoelectrode in ionic communication with the oxidant and/or reductant portions whereby electrons or electron holes are transmitted to the reductant or oxidant portion, respectively, while the at least one photoelectrode is illuminated; an external rectified electrical circuit between the semiconductor and its counterelectrode for charging; and an external loaded electrical circuit for withdrawal of electrical energy from the oxidant and reductant portions.
2. Description of the Prior Art
The direct conversion of solar energy to electricity can be achieved by solid state photovoltaic cells, such as those using silicon solar arrays. While such direct conversion has been viable for specialized application, the costs have been too high for acceptance for general electricity generation. Additionally, storage of electricity generated by the solid state photovoltaic cells has presented both technical and economic problems. The electricity storage has been generally performed by use of large storage batteries. Attempts are continuing to arrive at advanced battery systems which would provide technical and economic viability for such storage. Another method of conversion of solar energy to electrical energy in a single device is the photoelectrogenerative cell suggested by U.S. Pat No. 4,037,029 wherein an electrolytic cell anolyte contains photoelectrogenerative materials.
U.S. Pat. No. 4,021,323 teaches the conversion of solar energy to electrical energy by using solid state photovoltaic generators to electrolyze an electrolyte thereby producing hydrogen for use in a fuel cell for production of electrical energy.